Megasquirt help

[rod2190]

Had I question just had my car dyno tuned it's an 86 635csi turbo b35 head on b34 block b34 intake manifold my car made 300whp and 355wtq at 15.5 psi I was planning on running 22psi but the tuner did not want to go any further due to "noise" in my tps and coolant temp signals can anyone give me some pointers on how to take care of this or diagnos if not I will run shielded wire outside my stock harness. (Motrnic 36 pin plug and play ms2 extra) any answers would be much appreciated

[marc79euro645]

Not sure about TS, but in megatune under settings/general settings you can adjust lag factoring for all sensor inputs. That should tune out excess noise.
good luck
marc

[PDX5]

Double check your sensor ground.

Sensors should ground at the MS box and not chassis. Don't assume the MSPNP2 is wired correctly. I rewired my M1.3 harness and now I have zero TPS noise and without a lag factor (100%) or shielded wire.

http://msextra.com/doc/general/grounding.html

[rod2190]

I pulled up electrical trouble shooting diagram for 86 and it shows the coolant temp and tps are grounded to the block above the starter should I remove those grounds and leave it that way or should I run new grounds to ms2?

[marc79euro645]

Thats a good place to ground your megasquirt.

[PDX5]

Run new grounds, or do a quick datalog with some jumper wires bypassing the original ground wires and going straight to the MS. You should see a significant improvement. Once you find a correct ground scheme you can solder and make neat permanent connections (use the wires at the ecu end instead of the individual sensors. A small bypass at the ecu for all the sensor grounds should work neatly).

From the link I posted above:

If re-using or splicing into OEM wiring, do not assume that their wiring is ok. Always follow the above principles.
As a check, with the Megasquirt connector unplugged, ensure that the sensor grounds have no continuity to engine/body ground. Your sensor readings will be junk if they do - the sensors must ground at the Megasquirt only.

[rod2190]

Thanks I will re-wire